Can my password change in XP?

I had my laptop repaired at a shop because of a broken dc jack. Before I gave it to them I put a password on the login to XP. When I received my computer back the password I picked doesn't work now. Is there anyway they could have changed it? I know it's not that I forgot the password.

I didn't have time to ask did they change the password as the laptop was just delivered to me this morning. I'll check the recommendations ya'll gave when I get home tonight and give a update on the results.